A conventional lock device includes a lock and a key. The lock includes a core body and a plurality of pins. The core body extends along a central axis, and has a plurality of helical keyways and a plurality of through holes. Each of the helical keyways is formed in an outer surrounding surface of the core body, and extends about the central axis. Each of the through holes is formed in the outer surrounding surface of the core body, extends through the central axis, and is in spatial communication with a respective one of the helical keyways. The pins are respectively and movably mounted in the through holes, and respectively extend into the helical keyways. The key has a plurality of helical blades that respectively correspond to the helical keyways. Each of the helical blades has a recess that is formed in an inner helical surface thereof. When the helical blades are respectively inserted into the helical keyways, each of the pins has an end engaging the recess of the corresponding one of the helical blades and an opposite end flush with the outer surrounding surface of the core body.
However, since each of the through holes extends through the central axis of the core body, the core body must be made of a relatively high-strength material for maintaining a sufficient structural strength thereof. Moreover, it may be difficult to form the recess in the inner helical surface of each of the helical blades.